We exploit the regenerative capacity of the peripheral nervous system and the plasticity of the central nervous system (CNS) to promote recovery of motor function following spinal cord injury. A peripheral nerve is detached from its target muscle above the lesion and the cut end is inserted into the undamaged spinal cord below the lesion. We propose that novel synaptic connections will form between motor axons in the inserted nerve and the spinal neurons below the lesion. These new connections can be under voluntary supraspinal control because inputs from the brain to the regenerating motor axons are intact. Aim 1. How does the topographic distribution of regenerating T13 axons change during the period following nerve insertion? Aim 2. What is the distribution of synaptic contacts made by regenerating T13 motor axons on lumbar motoneurons and interneurons? Histology, confocal microscopy, and microsurgical techniques will be used to investigate these aims. We take one neural system which has evolved extensive regeneration capabilities, combine it with another neural system shown to be incredibly plastic and adaptive and use their combined strengths to overcome a debilitating injury.